Cutting tools are used for removing material from a workpiece in order to manufacture therefrom a desired final element. There exists in common practice a great variety of operations for the removal of material, for each of which, a specific tool is designed, which may be in the form of a single body or in the form of a tool holder with one or more replaceable cutting inserts mounted thereon. Examples of such operations are drilling, milling, turning, boring etc.
A majority of cutting tools or cutting inserts are formed with a cutting edge adapted to come in contact with the workpiece, within a cutting zone, so as to remove material therefrom during a cutting operation, the removed material being in the form of a chip.
Each cutting edge of a cutting tool or cutting insert is known to have a rake surface extending from the cutting edge in the direction away from the workpiece and a relief surface extending from the cutting edge transversely to the rake surface and generally facing in the direction of the workpiece, the cutting edge being defined at the intersection between its rake and relief surfaces.
The rake surface is adapted to come in contact with the removed chip, while the relief surface is generally designed so as not to come in contact with the workpiece during cutting operation.
Cutting tools are designed so that the angle between the rake and the relief surface allows positioning the cutting tool with respect to the workpiece during a cutting operation in a way preventing the relief surface from coming in contact with the workpiece while providing a sufficient cutting angle and support to the cutting tool to obtain (a) efficient removal of chips from the workpiece and (b) sufficient mechanical integrity to the cutting edge.
Cutting tools are used for removing material from a workpiece to manufacture therefrom of desired final element. There exists in common practice a great variety of operations for the removal of material, for each of which, a specific tool is designed. Examples of such operations are drilling, milling, turning, boring etc.
The majority of cutting tools are formed with a sharp cutting edge adapted to come in contact with the workpiece, within a cutting zone, to remove material therefrom in the form of a chip, in a process referred to as chipping. During such process there is usually provided a linear displacement of the cutting tool relative to the workpiece, referred to as ‘feed’ and either rotation of the cutting tool with respect to the workpiece, such as e.g. in milling and drilling, or rotation of the workpiece with respect to the cutting tool, such as e.g. in turning.
Chips must be evacuated continuously during chipping and any congestion may rapidly lead to high loads, overheating and consequent break-down and failure of the cutting tool.
The cutting edge of a cutting tool is generally defined as an intersection line between a rake surface and a relief surface.
The rake surface is adapted to come in contact with the removed chip and, as such, its geometry influences the length and geometry of the removed chip, and more importantly, the manner of evacuation of the chip from the cutting zone.
The relief surface is generally designed so as not to come in contact with the portion of the workpiece from which the chip has been removed. Depending on the angle between the relief surface and the rake surface, the cutting tool is positioned such as to avoid contact between the relief surface and the workpiece.
It has been known to provide additional elements on the relief surface, for example, elements configured for deforming the workpiece prior to the cutting operation, for example, as set forth by the applicant himself in WO09053803.
Furthermore, the additional elements are also known to being used as cutting elements, as set forth by the applicant himself in WO11001438.
Cutting tools are used for removing material from a workpiece in order to manufacture therefrom a desired final element. There exists in common practice a great variety of operations for the removal of material, for each of which, a specific tool is designed, which may be in the form of a single body or in the form of a tool holder with one or more replaceable cutting inserts mounted thereon. Examples of such operations are drilling, milling, turning, boring etc.
A majority of cutting tools or cutting inserts are formed with a cutting edge adapted to come in contact with the workpiece, within a cutting zone, so as to remove material therefrom during a cutting operation, the removed material being in the form of a chip, and the process of forming chips being known as chipping.
During a cutting operation there is usually provided a linear displacement of the cutting tool relative to the workpiece, referred to as ‘feed’ and either rotation of the cutting tool about its central axis with the workpiece being stationary, such as e.g. in milling and drilling operations, or rotation of the workpiece about its central axis with the tool moving only linearly such as e.g. in turning, slotting, parting and the like.
Chips must be evacuated continuously during chipping and any congestion may rapidly lead to high loads, overheating, quick wear and consequent break-down, failure or malfunction of the cutting tool or cutting insert.
Each cutting edge of a cutting tool or cutting insert is known to have a rake surface extending from the cutting edge in the direction away from the workpiece and a relief surface extending from the cutting edge transversely to the rake surface and generally facing in the direction of the workpiece, the cutting edge being defined at the intersection between its rake and relief surfaces.
The rake surface is adapted to come in contact with the removed chip and may have chip deforming/splitting/breaking or the like means whose design is such as to facilitate the evacuation of the chip from the cutting zone.
The relief surface is generally designed so as not to come in contact with the workpiece during cutting operation. With a given angle between the relief and rake surfaces of each cutting edge, this is achieved by the cutting tool/cutting insert being positioned during cutting operation such as to provide a distance between the relief surface and the workpiece, said distance normally increasing in the direction away from the cutting edge.
During a cutting operation, the amount of material to be removed per time unit by a given cutting tool from a given workpiece, and particularly, the thickness of the chip removed, depends on a number of parameters including the speed of rotation YR of the cutting tool relative to the workpiece and the feed F.
On the other hand, the above parameters have a drastic influence on loads exerted on the cutting tool during chipping. The loads exerted on the cutting tool may be so high as to cause damage thereto, rendering it useless. On top of this, friction of the cutting tool with the workpiece causes heating of the former and the latter at the cutting zone, due to which extensive cooling, usually by means of a cooling liquid, is normally required. To avoid undesirable cutting conditions, the feed F and rotation speed YR are thus limited, and so is, as a consequence, the power used.